The effects of lapping load in finishing advanced ceramic balls on a novel eccentric lapping machine

Authors: Kang, J. and Hadfield, M.

Journal: Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

Volume: 219

Issue: 7

Pages: 505-513

ISSN: 0954-4054

DOI: 10.1243/095440505X32427

Abstract:

Hot isostatically pressed silicon nitride ball blanks were lapped from a diameter of 13.255mm to a diameter of 12.7mm by a novel eccentric lapping machine. A maximum material removal rate of 68 μm/h has been achieved under a nominal lapping load of 43 N per ball. It was found that the material removal rate increased almost linearly with the lapping load within this load range. When the lapping load was higher than 43 N per ball, the material removal rate started to drop and the lapped ball roundness error started to increase. At the highest nominal lapping load of 107 N per ball, surface damage and subsurface damage were found on the lapped balls. Because of the eccentric loading effect, the actual load on an individual ball could be 25-28 per cent higher than the nominal lapping load. The surface residual stresses of lapped balls under different lapping loads were measured, and it was found that the lapping load had less effect than the previous hot isostatic pressing process. Rolling contact fatigue tests were conducted on balls lapped at nominal loads of 43 and 107 N per ball. No failure occurred on the ball lapped at 43 N per ball after 138 × 106 stress cycles. The ball lapped at 107 N per ball failed after 13.3 × 106 stress cycles with a shallow spall with a flat bottom inside. This research suggests that the lapping load for advanced ceramic balls in conventional concentric lapping could be doubled from 20 to 40 N per ball without degrading the surface quality of lapped balls. © IMechE 2005.

Source: Scopus

The effects of lapping load in finishing advanced ceramic balls on a novel eccentric lapping machine

Authors: Kang, J. and Hadfield, M.

Journal: PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART B-JOURNAL OF ENGINEERING MANUFACTURE

Volume: 219

Issue: 7

Pages: 505-513

ISSN: 0954-4054

DOI: 10.1243/095440505X32427

Source: Web of Science (Lite)

The effects of lapping load in finishing advanced ceramic balls on a novel eccentric lapping machine

Authors: Kang, J. and Hadfield, M.

Journal: Proceedings of the Institution of Mechanical Engineers Part B: Journal of Engineering Manufacture

Volume: 219

Pages: 505-513

ISSN: 0954-4054

DOI: 10.1243/095440505X32427

Abstract:

Hot isostatically pressed silicon nitride ball blanks were lapped from a diameter of 13.255 mm to a diameter of 12.7 mm by a novel eccentric lapping machine. A maximum material removal rate of 68 μm/h has been achieved under a nominal lapping load of 43 N per ball. It was found that the material removal rate increased almost linearly with the lapping load within this load range. When the lapping load was higher than 43 N per ball, the material removal rate started to drop and the lapped ball roundness error started to increase. At the highest nominal lapping load of 107 N per ball, surface damage and subsurface damage were found on the lapped balls. Because of the eccentric loading effect, the actual load on an individual ball could be 25-28 per cent higher than the nominal lapping load. The surface residual stresses of lapped balls under different lapping loads were measured, and it was found that the lapping load had less effect than the previous hot isostatic pressing process. Rolling contact fatigue tests were conducted on balls lapped at nominal loads of 43 and 107 N per ball. No failure occurred on the ball lapped at 43 N per ball after 138 x 106 stress cycles. The ball lapped at 107 N per ball failed after 13.3 x 106 stress cycles with a shallow spall with a flat bottom inside. This research suggests that the lapping load for advanced ceramic balls in conventional concentric lapping could be doubled from 20 to 40 N per ball without degrading the surface quality of lapped balls.

http://journals.pepublishing.com/content/7j0x2411x331t523/

Source: Manual

Preferred by: Mark Hadfield